Translation:

9. See they not what is before them and behind them of the sky and the earth? If We wished We could cause the earth to swallow them up or cause a piece of the sky to fall upon them. Verily in this is a Sign for every devotee that turns to Allah (in repentance).

Notes (Tafseer)

3796. The men who walk in spiritual darkness and laugh at a Hereafter have but to observe the Power of Allah in the nature around them. He Who created the heavens and the earth and sustains them can surely make a new Creation! And the cosmic Laws which are so just and inevitable should surely give them an idea of the inexorable Justice that must redress all balance.

3797. Cf. xvi. 45, and n. 2071. Who are these puny creatures-sceptics that question the might and majesty of Allah?

3798. Cf. xxvi. 187. This was actually a challenge hurled at Shu'aib and a shower of ashes and cinders came from above and overwhelmed the challengers!